模拟失重对大鼠听功能及耳蜗带状突触的影响  

Effects of simulated weightlessness on auditory function and cochlear synapses of rats

作　　者：李元超 吴玮[1,2,3] 王刚 屈昌北 王磊 李保卫 韩浩伦 李丹 刘钢 LI Yuanchao;WU Wei;WANG Gang;QU Changbei;WANG Lei;LI Baowei;HAN Haolun;LI Dan;LIU Gang(Department of Otolaryngology,306 th Hospital of PLA-PeKing University Teaching Hospital,Beijing 100101,China;Department of Otolaryngology,Strategic Support Force Characteristic Medical Center of PLA;State Environmental Protection Key Laboratory of Environmental Sense Organ Stress and Health;School of Public Health,Capital Medical University)

机构地区：[1]北京大学解放军306医院教学医院耳鼻咽喉科,北京100101 [2]中国人民解放军战略支援部队特色医学中心耳鼻咽喉科 [3]国家环境保护环境感官应激与健康重点实验室 [4]首都医科大学公共卫生学院

出　　处：《山西医科大学学报》2021年第5期638-642,共5页Journal of Shanxi Medical University

基　　金：航天医学基础与应用国家重点实验开放课题(SMFA19K06);军队医学科技青年培育计划项目(20QNPY067);战略支援部队特色医学中心医药卫生军事医学研究课题(19ZX29)。

摘　　要：目的观察模拟失重对大鼠听功能的影响及耳蜗带状突触(RS)的损伤,探讨失重对听觉系统的损伤机制。方法48只SD大鼠随机分为模拟失重组和空白对照组,各24只;再依据暴露时间随机分为1周、4周组,各12只24耳。在暴露前(B0)、暴露结束后即刻(P0)和脱离暴露环境7 d(P7)进行双耳听性脑干反应(ABR)阈值和畸变产物耳声发射(DPOAE)检测,并于P0和P7时测听结束后分别处死每组一半(6只)大鼠再分离双侧耳蜗。采用C末端结合蛋白2(CtBP2)抗体对内毛细胞突触带状体进行免疫荧光标记并计数,评估RS损伤。结果模拟失重1周组P0时ABR阈值较B0时升高;在P0时模拟失重4周组ABR阈值较模拟失重1周组升高(P<0.05);两个模拟失重组大鼠ABR阈值在P7时均恢复,与B0时差异无统计学意义。在各个时间点四组大鼠DPOAE引出率差异均无统计学意义。在P0时,模拟失重1周组带状体数量较空白对照1周组明显减少,而模拟失重4周组较模拟失重1周组减少(P<0.001);P7时模拟失重1周组和模拟失重4周组带状体数量较P0时均增多,差异有统计学意义,但仍少于空白对照1周组和空白对照4周组(P<0.001)。RS数量与ABR阈值呈负相关(r=-0.759,P=0.029)。结论4周内随着模拟失重时间延长,大鼠ABR阈值进行性升高,RS数量进行性下降;脱离失重环境后ABR阈值可在7 d内恢复正常,而RS数量未能完全恢复,部分RS可能已发生永久性损伤,提示RS损伤是失重状态下听觉系统的早期改变,并可能是早期听功能改变的重要机制。Objective To observe the effect of simulated weightlessness on auditory function and cochlear ribbon synapse(RS)in rats,and to explore its mechanism.Methods Forty-eight SD rats were randomly divided into simulated weightlessness group and blank control group(24 rats in each group),and then randomly divided into 1-week group and 4-week group according to exposure time(24 ears in each group).ABR threshold and DPOAE were measured before exposure(B0),immediately after exposure(P0)and 7 d after exposure(P7).At the end of audiometry at P0 and P7,six rats(12 ears)in each group were killed,and then bilateral cochleae were isolated.The synaptic ribbons of inner hair cells were labeled with C-terminal binding protein 2(CtBP2)antibody by immunofluorescence and were counted to evaluate RS injury.Results ABR threshold in simulated weightlessness 1-week group was higher at P0 than that at B0,and it was higher in simulated weightlessness 4-week group than in simulated weightlessness 1-week group(P<0.05).ABR threshold recovered at P7 in two simulated weightlessness groups,and showed no significant difference compared with that at B0.There was no significant difference in DPOAE extraction rate among the four groups at each time point.At P0,the number of synapse ribbons in simulated weightlessness 1-week group was significantly less than that in blank control 1-week group,and it was lower in simulated weightlessness 4-week group than that in simulated weightlessness 1-week group(P<0.001).The number of synapse ribbons in simulated weightlessness 1-week group and 4-week group were higher at P7 than those at P0,but still less than those in blank control 1-week group and blank control 4-week group(P<0.001).RS number was negatively correlated with ABR threshold(r=-0.759,P=0.029).Conclusion Within four weeks of simulated weightlessness,ABR threshold is gradually increased and RS number is gradually decreased.After removing exposure factors,ABR threshold could return to the normal within 7 d,but RS number could not completely recover,and

关 键 词：失重 听性脑干反应 畸变产物耳声发射 内毛细胞 带状突触 

分 类 号：R764[医药卫生—耳鼻咽喉科]